1. Field of the Invention
The present invention is directed to a method and a system for processing print data. It is particularly directed to system for processing larger print jobs wherein a print job comprises a plurality of documents and/or pages. It is therefore suited for application in print production environments as occur in larger computer centers or in what is referred to as the “printing on demand” (PoD) market.
2. Description of the Related Art
Such print production systems are described, for example, in the publication Das Druckerbuch, edited by Dr. Gerd Goldmann, OÓce Printing Systems GmbH, Edition 4a, May 1999 (ISBN 3-00-001019-x), pages 12-1 through 12-17. Pages 12-9 through 12-11 in this publication describe what is referred to as a print job manager with which print jobs (also referred to as job tickets) can be generated in an ordinary (or arbitrary) computer (referred to here as a client PC) linked to a computer network, and the print jobs generated in this way can be transmitted to a system component (for example, an order distribution system) for further-processing and ultimate printout.
During the course of processing a print job that precedes the actual printing event on a printer device, it is often desirable to check the printed result in advance (referred to as a preview). U.S. Pat. No. 5,963,641 discloses a method and device for processing print data the satisfies this desire.
The preview function becomes especially important in network-based print production environments wherein a plurality of user terminals (client PCs) are connected to a shared network, as are one or more print servers that administer print data generated by the users or by a host printer and forward them to one or more high-performance printers. This is especially true of print data streams wherein the print data is composed of a plurality of data sources, for example of a variable data stream and of static resource data to be integrated therein. Examples of such data streams are what is referred to as the Advanced Function Presentation Data Stream (AFPDS) or the Mixed Object Documents Contents Architecture data stream (MO:DCA).
The AFPDS data stream as well as an image viewer which is suitable for the data are described, for example, in documentation number S54405285-00 of International Business Machines Corporation (IBM) bearing the title “AFP Conversion and Index Facility (ACIF) Users Guide”. The MO:DCA data stream is described, for example, in IBM document number SC31-6802-04 bearing the title “Mixed Object Document Content Architecture Reference”.
Networked devices are being increasingly utilized in printing processes, and the devices are driven or monitored by means of standard computer programs such as, for example, known browser programs. Such Internet browsers are, for example, the Microsoft Internet Explorer® browser operating under the Windows operating system, the Netscape Navigator® browser or the browser Opera that can also be employed under the Linux operating system. Such browser programs are often included in the standard software package of personal computers and are thus available at nearly every newer type of personal computer.
The Netscape Navigator browser supports what is referred to as a layer technique that is programmable in the JavaScript programming language. The object layer that lies below the document object in the JavaScript® object hierarchy thereby provides the possibility of obtaining access to all layers that are defined in an HTML data file.
A new layer object is automatically generated when the browser program encounters a layer in the HTML data file.
Layers can be addressed in various ways with JavaScript®, for example with the commands
“document.layers[#].Property=Value”
“document.layers[#].Method ο”
“Color=document.layers [0].bgColor”
“document.LayerName.Property=Value”
“document.LayerName.Methodο” and
“Color=document.Headerarea.bgColor”
A layer can thereby be addressed with an index number and “document.layers”. Which layer in the data file is to be called follows this in brackets. Each layer that was noted in HTML with the <layer>-tag or with the <ilayer>-tag counts. The layers can also be addressed with “document.LayerName” and the name can be indicated that was specified in the attribute “name=” in the introductory <layer>/<ilayer>-tag in the definition of the graphic.
Further details about this layer technique are described, for example, in the book “SELFHTML: Version 7.0 of 27 Apr. 1998” by Stefan Müz that can be ordered via the Internet.
The aforementioned publications and patents are herewith incorporated by reference into the present specification.
When processing print jobs, PoD applications demand that successive pages of a document be printed exactly registered, particularly when producing bound brochures.